Recent study has found out that after multiple times of recompression, the DCT coefficients of JPEG image can form an embedding domain that is robust to recompression, which is called transport channel matching (TCM) method. Because the cost function of the adaptive steganography does not consider the impact of modification on the robustness, the modified DCT coefficients of the stego image after TCM will change after recompression. To reduce the number of changed coefficients after recompression, this paper proposes a robust steganography algorithm which dynamically updates the robustness cost of every DCT coefficient. The robustness cost proposed is calculated by testing whether the modified DCT coefficient can resist recompression in every step of STC embedding process. By adding robustness cost to the distortion cost and using the framework of STC embedding algorithm to embed the message, the stego images have good performance both in robustness and security. The experimental results show that the proposed algorithm can significantly enhance the robustness of stego images, and the embedded messages could be extracted correctly at almost all cases when recompressing with a lower quality factor and recompression process is known to the user of proposed algorithm.

翻译：近期研究发现，JPEG图像经多次重压缩后，其DCT系数可形成对重压缩具有鲁棒性的嵌入域，该方法被称为传输通道匹配（TCM）算法。由于自适应隐写的代价函数未考虑修改操作对鲁棒性的影响，经TCM处理后，隐写图像的DCT系数在重压缩后会发生改变。为减少重压缩后系数变化的数量，本文提出一种动态更新每个DCT系数鲁棒代价的鲁棒隐写算法。该鲁棒代价通过逐次检验STC嵌入过程中被修改的DCT系数能否抵抗重压缩计算得到。通过将鲁棒代价加入失真代价，并利用STC嵌入算法框架进行信息嵌入，所得隐写图像在鲁棒性与安全性方面均表现出良好性能。实验结果表明，所提算法能显著增强隐写图像的鲁棒性，当采用较低质量因子重压缩且用户已知重压缩过程时，嵌入信息几乎在所有情况下均可正确提取。